Liquid crystal display device and method for fabricating the same

ABSTRACT

The present invention discloses a method of manufacturing a liquid crystal display device, including depositing a first metal layer on a transparent substrate; patterning the metal layer to form a gate line, the gate line having a gate electrode portion; depositing sequentially an insulating layer, an amorphous silicon layer and a doped amorphous silicon layer on the exposed surface of the transparent substrate while covering the gate line; patterning the amorphous silicon layer and the doped amorphous silicon layer to form a semiconductor island; depositing a second metal layer on the exposed surface of the insulating layer while covering the semiconductor island; patterning the second metal layer to form a source electrode, a drain electrode, and a capacitor electrode, the drain electrode spaced apart from the source electrode; etching the doped amorphous silicon layer of the semiconductor island to from an active area; forming a passivation film over the whole surface of the substrate while covering the source electrode, the drain electrode and the capacitor electrode; depositing a transparent conductive material layer on the passivation film; applying a negative photoresist on the transparent conductive material layer; performing a back side exposure to form a first exposed portion of the negative photoresist; aligning a patterning mask with the negative photoresist; performing a front side exposure to form a second exposed portion of the negative photoresist, the second exposed portion overlapping the first exposed portion; baking the transparent conductive material layer; and patterning the transparent conductive material layer to form a pixel electrode.

CROSS REFERENCE

[0001] This application claims the benefit of Korean Patent ApplicationNo. 1999-31487, filed on Jul. 31, 1999, under 35 U.S.C. §119, theentirety of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a liquid crystal display (LCD)device, and more particularly, to a liquid crystal display device havinga thin film transistor (TFT) and a method of manufacturing the same.

[0004] 2. Description of Related Art

[0005] A typical liquid crystal display device uses optical anisotropyand polarization properties of liquid crystal molecules. The liquidcrystal molecules have a definite orientational order in arrangementresulting from their thin and long shapes. The arrangement direction ofthe liquid crystal molecules can be controlled by supplying an electricfield to the liquid crystal molecules. In other words, as thearrangement direction of the liquid crystal molecules is changed, thearrangement of the liquid crystal molecules also changes. Since Incidentlight is refracted to the arrangement direction of the liquid crystalmolecules due to the optical anisotropy of the arranged liquid crystalmolecules image data can be displayed.

[0006] By now, an active matrix LCD that the thin film transistors andthe pixel electrodes are arranged in the form of a matrix is mostattention-getting due to its high resolution and superiority indisplaying moving video data.

[0007]FIG. 1 is a cross-sectional view illustrating a pixel of aconventional liquid crystal display device.

[0008] The liquid crystal display device 20 has a bottom substrate 2 anda top substrate 4 spaced apart from each other. The liquid crystaldisplay device further includes a liquid crystal layer 10 is injectedbetween the two opposite substrates 2 and 4 The top substrate 4 has acolor filter to display colors, and the bottom substrate 2 has switchingelements such as thin film transistors (TFTs) that applies electricalsignals to the liquid crystal layer 10 to change the arrangementdirection of the liquid crystal molecules of the liquid crystal layer10. Each of the TFTs “S” has a gate electrode 30, a source electrode 32and a drain electrode 34.

[0009] In detail, the top substrate 4 further includes a commonelectrode 12 covering the color filter layer 8. The common electrode 12plays a role of the first electrode to supply a voltage to the liquidcrystal layer 10. The bottom substrate 2 further includes a pixelelectrode 14. The pixel electrode 14 is electrically connected with thedrain electrode 34 of the TFT “S”. The pixel electrode 14 receiveselectrical signals from the thin film transistor “S”, and plays a roleof the second electrode to supply voltage to the liquid crystal layer10. A portion, on which the pixel electrodes 14 are formed, is definedas a pixel electrode portion “P”. In order to prevent leakage of theliquid crystal layer 10 disposed between the top substrate 4 and thebottom substrate 2, edge portions of the top substrate 4 and the bottomsubstrate 2 are sealed by a sealant 6.

[0010] Recently, as the display area of the liquid crystal displaydevice becomes larger, the fabricating process of the bottom substrate 2becomes complicated. That is to say, for a liquid crystal display devicehaving over 12 inch display area, a step-and-repeat exposure techniqueis applied to fabricating the bottom substrate. The step-and-repeatexposure technique is to perform at least two exposing steps with thesame patterned mask. The reason for the step and repeat technique to beapplicable to the bottom substrate is that the patterns formed on thebottom substrate are repeats of the same form.

[0011] Referring to the FIGS. 2 and 3, a batch exposure technique andthe step-and-repeat exposure technique are explained as follows.Referring to the FIG. 2 showing a patterning mask, in the batch exposuretechnique, a display area A, data pad portions D and E and gate padportions B and C surrounding the display area “A” are formed at one timewith the patterning mask.

[0012] The batch exposure technique is just applicable to the bottomsubstrate of the liquid crystal display device having a less than 10inch-sized display area. Namely, in case of the bottom substrate of theliquid crystal display device having a larger than 10 inch-sized displayarea, the batch exposure technique is useless due to the diffraction oflight incident from an exposure apparatus.

[0013] Referring to the FIG. 3 illustrating the step-and-repeat exposuretechnique, the display area is formed into a plurality of neighboringdisplay exposure regions like A1, A2, . . . , A9, sequentially. Each ofthe display exposure regions has an identical image projected ontoitself with a same display patterning mask.

[0014] By the same technique, the data pad portions are formed into aplurality of neighboring data exposure regions like D1, D2, D3 and E1,E2 E3 having an identical image, sequentially. And the gate pad portionsare formed into a plurality of neighboring gate exposure regions likeB1, B2, B3, C1, C2 and C3 having an identical image, sequentially.

[0015] The above-mentioned step-and-repeat exposure technique is morewidely used than the batch exposure technique as an exposure method.

[0016] But, to fabricate the liquid crystal display device using thestep-and-repeat exposure technique may give rise to a seriousdegradation of image quality at the display area. The reason is that thestep-and-repeat exposure technique needs at least over 40 processes ofphotolithography. Comparing with the step-and-repeat exposure technique,the batch technique needs at least just 5 processes of photolithography.Thus, no matter bow accurate exposure equipment and arrangementapparatus are used for the step-and-repeat exposure technique, it maygive rise to misalignment between the exposure regions.

[0017] For example, as shown in FIG. 4, the display exposure regions A7and A8, the display exposure region A7 includes a pixel electrode 71, ahalf of a data line 60, and a half of a data line 61. The displayexposure region Ag includes a pixel electrode 72, a half of a data line61, and a half of a data line 62. The display exposure regions A7 and A8include the data line 61 in common, and are divided by an imaginaryboundary line 50. That is to say, the display exposure regions A7 and A8differ in an exposed order with the imaginary boundary line 50 centeringon between the display exposure regions A7 and A8. That difference inthe exposed order may bring out a difference in distances between thepixel electrodes 71 and 72 and the data lines 60, 61 and 62. Since theexposure equipment or the arrangement apparatus has an accuracylimitation of itself, misalignment between the exposure regions mayoccur. The misalignment may result in shift, rotation and distortion ofthe patterns, thereby causing defects such as disconnection of thewirings and differences in electrical properties between the exposureregions.

[0018] Namely, the distance between the pixel electrode 71 and the dataline 60 is different from the distance between the pixel electrode 71and the data line 61. And, the distance between the pixel electrode 72and the data line 61 is different from the distance between the pixelelectrode 72 and the data line 62. The pixel electrodes 71 and 72 arethe pixel portions P1 and P2, respectively.

[0019] In other words, fabricating the thin film transistor by thestep-and-repeat exposure technique, it may bring about spotted effectsnear the boundaries of the neighboring display exposure regions resultedfrom the sudden difference in the distance between the pixel electrodesand the data lines at each exposure region.

[0020] In case of manufacturing the large-sized liquid crystal displaydevice using the step-and-repeat exposure technique, driving the liquidcrystal display device by a dot inversion method, it brings about thedifference in parasitic capacitance Cdp between the data line and theright and left pixel electrodes between exposure regions. The parasiticcapacitance Cdp is the critical factor directly affecting the brightnessof the display area. Thus, the difference in the parasitic capacitanceCdp brings about the difference in the brightness between the left pixelelectrode and the right pixel electrode with the center boundary linedifferentiating the left pixel electrode and the right pixel electrode.Namely, the detectable difference in brightness, or the spotted effectoccurs near the boundaries of the exposure regions.

SUMMARY OF THE INVENTION

[0021] It is therefore an object of the present invention to reduce thedetectable difference in brightness resulting from the difference indistance between pixel electrodes and data lines at the boundaries ofexposure regions for a liquid crystal display device having a largerdisplay area.

[0022] For the above object, in a preferred embodiment of the presentinvention, a method of manufacturing a liquid crystal display device,including depositing a first metal layer on a transparent substrate;patterning the metal layer to form a gate line, the gate line having agate electrode portion; depositing sequentially an insulating layer, anamorphous silicon layer and a doped amorphous silicon layer on theexposed surface of the transparent substrate while covering the gateline; patterning the amorphous silicon layer and the doped amorphoussilicon layer to form a semiconductor island; depositing a second metallayer on the exposed surface of the insulating layer while covering thesemiconductor island; patterning the second metal layer to form a sourceelectrode, a drain electrode, and a capacitor electrode, the drainelectrode spaced apart from the source electrode; etching the dopedamorphous silicon layer of the semiconductor island to from an activearea; forming a passivation film over the whole surface of the substratewhile covering the source electrode, the drain electrode and thecapacitor electrode; depositing a transparent conductive material layeron the passivation film; applying a negative photoresist on thetransparent conductive material layer; performing a back side exposureto form a first exposed portion of the negative photoresist; aligning apatterning mask with the negative photoresist; performing a front sideexposure to form a second exposed portion of the negative photoresist,the second exposed portion overlapping the first exposed portion; bakingthe transparent conductive material layer; and patterning thetransparent conductive material layer to form a pixel electrode.

[0023] The gate line further includes first and second light shieldingportion, the gate electrode portion interposed the first and secondlight shielding portions, the first and second light shielding portionsextended outward a direction perpendicular to the gate line. Anoverlapped portion that the first exposed portion overlaps the secondexposed portion is about 2 μm to about 4 μm in width. A temperature ofbaking the transparent conductive material layer is about 100° C. toabout 150° C.

[0024] In another aspect, a liquid crystal display device includes adisplay area including gate lines, data lines, and thin filmtransistors, the gate lines arranged in a direction, the data linesarranged a direction perpendicular to the gate lines, the thin filmtransistors arranged near cross points of the gate lines and the datalines; a gate pad portion having a plurality of gate pads, each of theplurality of the gate pads connected with the corresponding gate lines;a data pad portion having a plurality of data pads, each of theplurality of the data pads connected with the corresponding data lines;and a plurality of light shielding patterns arranged along and outsideedges of the display area, the light shielding patterns preventing lightfrom transmitting portions other than the display area and the gate anddata pad portions.

[0025] The light shielding patterns are made of an opaque material. Thelight shielding patterns are selected from a group consisting ofchromium (Cr), aluminum (Al), antimony (Sb), tungsten (W), tantalum(Ta), molybdenum (Mo) and amorphous silicon. The light shieldingpatterns includes two gate light shielding patterns and two data lightshielding patterns, the two gate light shielding patterns arranged in adirection parallel to the data lines and spaced apart from each otherwith the display area therebetween, the two data light shieldingpatterns arranged in a direction parallel to the gate lines and spacedapart from each other with the display area therebetween. The lightshielding patterns including a plurality of light shielding patterns,the plurality of the light shielding patterns spaced apart from eachother, both end portions of each of the plurality of the light shieldingpatterns overlapping a portion of the gate lines or the data lines.

[0026] In another aspect, a method of fabricating an array substrate ofa liquid crystal display device including a transparent substrate and aplurality of gate and data pads, the method includes forming a pluralityof gate lines and a plurality of gate pads, the plurality of the gatelines arranged in a direction, each of the gate pads connecting with thecorresponding gate line outside the display area by a step-and-repeatexposure technique with a front-side exposure; forming data lightshielding patterns parallel to the gate lines between pre-positions ofthe data pads and the display area; forming a plurality of data linesand data pads, the plurality of the data lines arranged a directionperpendicular to the gate lines, each of the data pads connecting withthe corresponding data line outside the display area by thestep-and-repeat exposure technique with the front-side exposure; forminggate light shielding patterns parallel to the data lines between thegate pads and the display area; forming a thin film transistor arrangednear cross portion of the gate and data lines, the thin film transistorhaving a gate electrode, a source electrode and a drain electrode;depositing a transparent conductive layer and applying anegative-photoresist on the transparent substrate having the thin filmtransistors; forming a first exposed portion of the negative-photoresistby back-side exposure using the gate and data lines and the gate anddata light shielding patterns as a mask; forming a second portion of thenegative-photoresist using a step-and-repeat exposure by a front-sideexposure; backing the transparent conductive layer; and etching thetransparent conductive layer to form a pixel electrode.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] For a more complete understanding of the present invention andthe advantages thereof, reference is now made to the followingdescriptions taken in conjunction with the accompanying drawings, inwhich like reference numerals denote like parts, and in which:

[0028]FIG. 1 is a cross-sectional view illustrating a pixel of aconventional liquid crystal display device;

[0029]FIG. 2 is a plan view illustrating a patterning mask of theconventional liquid crystal display device;

[0030]FIG. 3 is a plan view illustrating a typical step-and-repeatexposure technique applied to a larger display area;

[0031]FIG. 4 is an expanded plan view illustrating exposure regionsproduced by the conventional step-and-repeat exposure technique;

[0032]FIG. 5 is a partially expanded plan view illustrating a pixel of aliquid crystal display device according to a preferred embodiment of thepresent invention;

[0033]FIG. 6 is an expanded plan view illustrating a gate line accordingto the preferred embodiment according to the present invention;

[0034]FIGS. 7A to 7F are cross-sectional views taken along a sectionline VII-VII of FIG. 5 respectively illustrating each process ofmanufacturing the liquid crystal display device according to thepreferred embodiment of the present invention;

[0035]FIG. 8 is a cross-sectional view taken along line VIII-VIII ofFIG. 5;

[0036]FIG. 9 is a plan view illustrating a thin film transistorsubstrate according to the preferred embodiment of the presentinvention;

[0037]FIG. 10 is an expanded plan view illustrating a portion “Z” ofFIG. 9; and

[0038]FIG. 11 is an expanded plan view illustrating a modified lightshielding pattern according to the preferred embodiment of the presentinvention.

DETAILED DESCRIPTION OF PREFFERED EMBODIMENTS

[0039] Reference will now be made in detail to the preferred embodimentof the present invention, example of which is illustrated in theaccompanying drawings.

[0040]FIG. 5 is a partially expanded plan view illustrating a pixel of aliquid crystal display (LCD) device according to a preferred embodimentof the present invention.

[0041] For the sake of convenience in explanation, describing theconstriction of the pixel regardless of process orders, the pixelincludes a gate line 100 arranged in a transverse direction, a data line108 arranged in a longitudinal direction perpendicular to the gate line100, pixel electrodes 114 disposed between a pair of the data lines 108and the gate line 100, and a thin film transistor (TFT) arranged nearthe cross point of the gate and data lines 100 and 108. The TFT includesa gate electrode 106, a source electrode 110 and a drain electrode 112.

[0042] The gate line 100 includes a gate electrode 106, and lightshielding portions 102 perpendicularly extended upward and downward fromthe gate line 100.

[0043] A data line 108 perpendicular to the gate line 100 has a drainelectrode 110 formed at a side portion and a source electrode 112 formedopposite to the drain electrode 110. The drain electrode 110 iselectrically connected with the pixel electrode 114 via a drain contacthole 120.

[0044] The pixel includes a storage electrode 116 formed over the gateline 100. The storage electrode 116 is electrically connected with thecorresponding pixel electrode 114 via a storage contact hole 118.

[0045]FIG. 6 is an expanded plan view of a gate line of the liquidcrystal display device according to the preferred embodiment of thepresent invention.

[0046] Shown in the FIG. 6 and described in FIG. 5, the gate line 100includes a gate electrode 106, and light shielding portions 102perpendicularly extended upward and downward from the gate line 100 andlocated near the gate electrode 106.

[0047] A major role of the light shielding portions 102 is to prevent UVlight from irradiating to a channel 104 of a thin film transistor duringa later process of forming a pixel electrode, i.e., the back-sideexposure, together with the gate line 100.

[0048]FIGS. 7A to 7F are cross sectional views taken along line VII-VIIof FIG. 5, illustrating a process for manufacturing the LCD device. Asshown in FIG. 7A, a metal layer is deposited on a transparent substrate1 and patterned so as to form the gate electrode 106 and the lightshielding portions 102. The metal layer preferably employs adual-layered structure of Molybdenum (Mo) and Aluminum-Neodymium (AlNd).Then, as shown in FIG. 7B, an insulating layer, an amorphous siliconlayer 132 and a doped amorphous silicon layer 134 are depositedsequentially and patterned so as to form a gate insulator 130 and anamorphous silicon amorphous silicon island 133.

[0049] Third, shown in FIG. 7C, a metal layer is deposited and patternedso as to form the source electrode 110, the drain electrode 112 and thestorage electrode 116. After that, the channel 104 is formed by etchingthe doped amorphous silicon layer 134 using the source electrode 110,the drain electrode 112 and the storage electrode 116 as a mask.

[0050] Hereinafter, the amorphous silicon island 133 can play a role asan active layer, since the amorphous silicon island 133 does not includethe doped amorphous silicon in the channel 104.

[0051] In other words, if not etching the channel 104, the amorphoussilicon island 133 can not play a role as a switching element because ithas no on/off characteristic.

[0052] Next, as shown in FIG. 7D, a passivation film 136 is depositedover the whole surface of the substrate 1 while covering the source anddrain electrodes 110 and 112. A portion of the passivation film 136 onthe drain electrode 112 is etched to form the drain contact hole 103.After forming the drain contact holes 102, a transparent conductiveelectrode 138 is deposited on the passivation film 136, and then, anegative-photoresist 140 is applied on the transparent conductive layer138. The negative-photoresist 140 has a characteristic that a portionof, for example, the transparent conductive electrode that is notexposed to light is etched away.

[0053] In the preferred embodiment of the present invention, the pixelelectrode 114 is formed by a self-aligning technology using thenegative-photoresist 140. That is to say, in order to form the pixelelectrode 114, the array substrate 1 is subjected to both a front-sideexposure and a back-side exposure. More specifically, when light isshone from below the transparent substrate 1 for the back-side exposure,the patterned gate electrode 106 acts as a mask, and when light is shonefrom above the transparent substrate 1 for the front-side exposure, theseparate patterning mask is used.

[0054] After applying the negative-photoresist 140 on the transparentconductive electrode, as explained above, light is shone from below thetransparent substrate 1 so as to form a first exposed portion 140 a ofthe negative-photoresist 140.

[0055] Next, shown in FIG. 6E, after aligning a patterning mask 142 overthe negative-photoresist 140, TV light is illuminated from above thepattern mask 142 so as to form a second exposed portion 104 b of thenegative-photoresist 140. At this point, it is preferred that a littleoverlap 140 c exists between the first exposed portion 140 a and thesecond exposed portion 140 b in order to prevent a possible line open ofthe transparent conductive electrode 138 at a position corresponding toa boundary between the first exposed portion 140 a and the secondexposed portion 140 b in a later etching process. The width of theoverlap 140 c is preferably about 2 to about 4 μm. After the front-sideexposure, the negative-photoresist 140 is baked and etched to form thepixel electrode 114 as shown in FIG. 7F. The post exposure baking (PEB)temperature is preferably between about 100° C. and about 150° C.

[0056] The pixel electrode 114 includes a first pixel portion 114 aproduced by the backside exposure and a second pixel portion 114 bproduced by the front-side exposure.

[0057] The preferred embodiment of the present invention may besummarized as follows: forming the gate electrode (a first step);forming a semiconductor area (a second step); forming the source anddrain electrodes (a third step); forming the passivation film (a fourthstep); and forming the pixel electrode (a fifth step). The preferredembodiment of the present invention, except for the fifth step offorming the pixel electrode 114, the step-and-repeat exposure techniquewith the front-side exposure is basically employed for pattering. Forthe step of forming the pixel electrode 114, the self-aligning techniquewith the back-side exposure and the step-and-repeat exposure techniquewith the front-side exposure are used together in order to prevent thedifference in brightness resulting from the misalignment between thedata lines and the pixel electrodes, which may occur only when using thestep-and-repeat exposure technique. That is to say, by using theself-aligning technique with the back-side exposure and thestep-and-repeat exposure technique with the front-side exposure togetherfor forming the first pixel portion of the pixel electrode, the possiblespotted effects on the display area of the liquid crystal display deviceproduced when using only the step-and-repeat exposure technique can beexcluded. Further, the problem of using only the batch technique andresulting from the refraction of light can be excluded by applying thestep-and-repeat exposure technique to forming the second pixel portionof the pixel electrode which is much more delicate than the first pixelportion.

[0058] The above advantage is explained in detail referring to FIG. 8showing a cross-sectional view taken along line VIII-VIII of FIG. 5.Shown in FIG. 8, the data lines 108 are formed on the transparentsubstrate 1, and the insulating layer 130 is formed on the data lines108. Between the adjacent two data lines 108, the second pixel portion114 b of the pixel electrode 114 is formed on the insulating layer 130.The first pixel portion 114 a of the pixel electrode 114 is not shown inthis cross-sectional view. The data lines 108 are at a distance of L6,L7, L8 and L9 from the adjacent pixel portion 114 b, respectively. Allof the spaced distances L6, L7, L8 and L9 are almost same because thepixel portions 114 b of the pixel electrode 114 are formed by the batchexposure technique with the back-side exposure described in FIG. 7D. Thewidth of the spaced distance can be controlled, and is preferably around1 μm.

[0059] In the preferred embodiment of the present invention, thenegative-photoresist 140 is used to form the pixel electrode 114. Thepixel electrode 114 is formed only on the display area. Since thenegative-photoresist 140 has a characteristic that a portion of forexample, a transparent conductive electrode that is not exposed to lightis etched away, it is preferred that separate light-shielding patternsare formed alogn and outside the display area for UV light to beirradiated only to the display area during the back side exposure so asnot to leave useless transparent conductive portions which has the samematerial as the pixel electrode 114.

[0060]FIG. 9 shows the TFT array substrate of the liquid crystal displaydevice according to the preferred embodiment of the present invention.As shown in FIG. 9, the array substrate 2 has a display area 150, a gatepad portion 160 including a plurality of gate pads 165 and a data padportion 170 including a plurality of data pads 175. Each of the gatepads 165 is connected to the corresponding gate line 100, and each ofthe data pads 175 is connected to the corresponding data line 108. Thegate pad portion 160 and the data pad portion 170 are formed along twoadjacent sides of the display area 150, respectively.

[0061] The TFT array substrate 2 further includes a plurality of staticelectricity protection portions 180. The static electricity protectionportion 180 is formed between the pad and the corresponding gate or dateline. The static electricity protection portions 180 serve to prevent astatic electricity, which may be produced in a process of manufacturingthe TFT array substrate 2, from destroying the insulation of the thinfilm transistors.

[0062] As described above, for forming the pixel electrode 114 of theliquid crystal display device according to the present invention, thenegative-photoresist 140 is used. Thus, light-shielding patterns arenecessary to be formed along and outside edges of the display area 150during the back-side exposure in order to illuminate light both thedisplay area and the pad areas. For the light-shielding patterns, thetwo gate light shielding patterns 167 are formed along an outside thedisplay device 150. The two gate light shielding patterns 167 are spacedapart from each other with the display area 150 therebetween. The twodata shielding patterns 177 are along an outside the display device 150.The two data light shielding patterns 177 are spaced apart from eachother with the display area 150 therebetween. The gate and data lightshielding patterns are perpendicular to each other. Preferably, the gateand data light shielding patterns constructs a rectangular shape and areelectrically connected with each other to form a equipotential. Thelight gate shielding pattern 167 and the data shielding pattern 177 aremade of a light-reflecting or absorbing material such as metal,amorphous silicon or black resin.

[0063]FIG. 10 is an expanded plan view of “Z” portion in FIG. 9. Asshown in FIG. 10, the gate and data light shielding patterns 167 and 177are formed along and outside the display area 150, respectively. Thegate light shielding patterns 167 are arranged in a direction parallelto the data lines, spaced apart from each other with the display area150 therebetween. The data light shielding patterns 177 are arranged ina direction parallel to the gate lines, spaced apart from each otherwith the display area 150 therebetween. The gate light shieldingpatterns 167 and the gate line 100 are formed at the same time, and thedata shielding pattern 177 and the data line 108 are formed at the sametime. Thus, an additional process is not required.

[0064] The gate and data shielding patterns 167 and 177 are formedindependent of the gate and data lines 100 and 108. Namely, the gateshielding pattern 167 is electrically independent of the gate line 108,and the data shielding pattern 177 is electrically independent of thedata line 100. The width of both the gate and data light shieldingpatterns 167 and 177 is preferably between about 50 μm and about 500 μm.

[0065]FIG. 11 is an expanded plan view illustrating a modified lightshielding pattern. As shown in FIG. 11, a plurality of data lightshielding patterns 177 are formed along and outside the display area150, and spaced apart from each other. Even though not shown, the gatelight shielding patterns are also formed along and outside the displayarea 150, and spaced apart from each other. Preferably, both endportions of each of the gate and data light shielding patterns 167 and177 overlap the gate and data lines 108, respectively.

[0066] As described above, in case of using the negative photoresist,the light shielding pattern serves to prevent UV light from transmittingportions other than the display area. In other words, when the pixelelectrode is formed by a self-aligning technique including the back-sideexposure using the negative photoresist, it is prevented to employ thelight-shielding patterns between the display area and the gate and datapad portions so that the transparent conductive material used as thepixel electrode is not formed on areas other than the display area.

[0067] As described herein-before, by manufacturing the LCD deviceaccording to the preferred embodiment of the present invention, sincedisplay distortion such as a difference in brightness can be removed,display quality can be improved.

[0068] While the invention has been particularly shown and describedwith reference to preferred embodiments thereof, it will be understoodby those skilled in the art that the foregoing and other changes in formand details may be made therein without departing from the spirit andscope of the invention.

What is claimed is:
 1. A method of manufacturing a liquid crystaldisplay device, comprising; depositing a first metal layer on atransparent substrate; patterning the metal layer to form a gate line,the gate line having a gate electrode portion; depositing sequentiallyan insulating layer, an amorphous silicon layer and a doped amorphoussilicon layer on the exposed surface of the transparent substrate whilecovering die gate line; patterning the amorphous silicon layer and thedoped amorphous silicon layer to form a semiconductor island; depositinga second metal layer on the exposed surface of the insulating layerwhile covering the semiconductor island; patterning the second metallayer to form a source electrode, a drain electrode, and a capacitorelectrode, the drain electrode spaced apart from the source electrode;etching the doped amorphous silicon layer of the semiconductor island tofrom an active area; forming a passivation film over the whole surfaceof the substrate while covering the source electrode, the drainelectrode and the capacitor electrode; depositing a transparentconductive material layer on the passivation film, applying a negativephotoresist on the transparent conductive material layer; performing aback side exposure to form a first exposed portion of the negativephotoresist; aligning a patterning mask with the negative photoresist;performing a front side exposure to form a second exposed portion of thenegative photoresist, the second exposed portion overlapping the firstexposed portion; baking the transparent conductive material layer; andpatterning die transparent conductive material layer to form a pixelelectrode.
 2. The method of claim 1, wherein the gate line furtherincludes first and second light shielding portion, the gate electrodeportion interposed the first and second light shielding portions, thefirst and second light shielding portions extended outward a directionperpendicular to the gate line.
 3. The method of claim 1, wherein aoverlapped portion that the first exposed portion overlaps the secondexposed portion is about 2 μm to about 4 μm in width.
 4. The method ofclaim 1m, wherein a temperature of baking the transparent conductivematerial layer is about 100° C. to about 150° C.
 5. A liquid crystaldisplay device, comprising: a display area including gate lines, datalines, and thin film transistors, the gate lines arranged in adirection, the data lines arranged a direction perpendicular to the gatelines, the thin film transistors arranged near cross points of the gatelines and the data lines; a gate pad portion having a plurality of gatepads, each of the plurality of the gate pads connected with thecorresponding gate lines; a data pad portion having a plurality of datapads, each of the plurality of the data pads connected with thecorresponding data lines; and a plurality of light shielding patternsarranged along and outside edges of the display area, the lightshielding patterns preventing light from transmitting portions otherthan the display area and the gate and data pad portions.
 6. The liquidcrystal display device of claim 5, wherein the light shielding patternsare made of an opaque material.
 7. The liquid crystal display device ofclaim 5, wherein the light shielding patterns are selected from a groupconsisting of chromium (Cr), aluminum (Al), antimony (Sb), tungsten (W),tantalum (Ta), molybdenum (Mo) and amorphous silicon.
 8. The liquidcrystal display device of claim 5, wherein the light shielding patternsincludes two gate light shielding patterns and two data light shieldingpatterns, the two gate light shielding patterns arranged in a directionparallel to the data lines and spaced apart from each other with thedisplay area therebetween, the two data light shielding patternsarranged in a direction parallel to the gate lines and spaced apart fromeach other with the display area therebetween.
 9. The liquid crystaldisplay device of claim 1, wherein the light shielding patternsincluding a plurality of light shielding patterns, the plurality of thelight shielding patterns spaced apart from each other, both end portionsof each of the plurality of the light shielding patterns overlapping aportion of the gate lines or the data lines.
 10. A method of fabricatingan array substrate of a liquid crystal display device including atransparent substrate and a plurality of gate and data pads comprising:forming a plurality of gate lines and a plurality of gate pads, theplurality of the gate lines arranged in a direction, each of the gatepads connecting with the corresponding gate line outside the displayarea by a step-and-repeat exposure technique with a front-side exposure;forming data light shielding patterns parallel to the gate lines betweenprepositions of the data pads and the display area; forming a pluralityof data lines and data pads, the plurality of the data lines arranged adirection perpendicular to the gate lines, each of the data padsconnecting with the corresponding data line outside the display area bythe step-and-repeat exposure technique with the front-side exposure;forming gate light shielding patterns parallel to the data lines betweenthe gate pads and the display area; forming a thin film transistorarranged near cross portion of the gate and data lines, the thin filmtransistor having a gate electrode, a source electrode and a drainelectrode; depositing a transparent conductive layer and applying anegative-photoresist on the transparent substrate having the thin filmtransistors; forming a first exposed portion of the negative-photoresistby back-side exposure using the gate and data lines and the gate anddata light shielding patterns as a mask; forming a second portion of thenegative-photoresist using a step-and-repeat exposure by a front-sideexposure, backing the transparent conductive layer; and etching thetransparent conductive layer to form a pixel electrode.
 11. The methodof claim 10, wherein the gate light shielding patterns are formed at thesame time as the gate lines, and the data light shielding patterns areformed at the same time as the data lines.
 12. The method of claim 10,wherein the gate and data light shielding patterns are made of amaterial selected from a group consisting of chromium (Cr), aluminum(Al), antimony (Sb), tungsten (W), tantalum (Ta), molybdenum (Mo) andamorphous silicon.